The present invention relates to splicing tapes suitable for splicing a leading edge portion of the outer turn of a roll of sheet material to another sheet material, and methods of making and using such splicing tapes.
Splicing tapes can be used for preparing a joint between two sheet materials such as, for example, between the leading edge portion of the outer turn of a roll of sheet material and another sheet material. The splicing operation can be performed in a static or a dynamic mode.
In the static mode, the first and second sheet material first may be positioned in the desired configuration relative to each other, and one or more splicing tapes are then applied to join the two sheets together. It is also possible to apply the splicing tape or tapes to one of the sheet materials first. Then the second sheet material is provided, positioned in the desired configuration and the two sheet materials are joined. Splices which are obtained in a static mode of preparation are often referred to as permanent splices. Some typical configurations of static splices are butt splices, overlap splices and staggered overlap splices. These configurations are shown and discussed in FIGS. 1A-1C of WO 95/29115.
It is often desirable, however, to prepare splices in a dynamic mode. This allows, for example, in the printing industry, joining the leading edge of the new roll of paper sheet material to the trailing edge of the old, depleting roll of paper sheet material without requiring interruption of the continuous production process. Splices which are obtained in a dynamic mode of operation are usually referred to as flying splices. A conventional way of making a flying splice tape uses destructible nose tabs as is described in WO 95/29115. In a first step the new roll is appropriately prepared or xe2x80x9cdressedxe2x80x9d for splicing, as is shown in FIG. 1a herein, which was taken from FIG. 3A of WO 95/29115. The leading edge 35 is formed by applying a double-sided adhesive tape in the form of a W or V or in another appropriate shape to the outermost turn 32 of the new roll of sheet material 30. The outermost lap 32 is then torn back against the tape to form the leading edge portion 35 which is releasably adhered to the next-to-the-outer turn 31 by the nose tabs 23. The new roll of sheet material 30 is then accelerated to the same speed as the running web sheet of the previous, depleting roll. The running web sheet is then pressed against the new roll 30 and pasted to the double-sided adhesive tape 25 on the outermost turn 32 of the new roll 30. The previous roll is typically cut off from the running web sheet. The nose tab is then subjected to the tractive force exerted by the running web sheet. The nose tab breaks thereby releasing the temporary joint between the outer turn 32 and the next-to-the-outer turn 31 of the new roll of sheet material 30. Another known configuration for applying a flying splice is shown in FIG. 1b herein which is adapted from FIG. 3B of WO 95/29115. Other splicing tapes useful for flying splices and static splices are discussed in U.S. Pat. Nos. 5,692,699 and 5,996,927.
Another useful splicing tape useful in preparing a flying splice is shown in EP 0 941 954. The ""954 reference discloses a splicing tape which uses a non-tacky polymer layer in contact with a carrier layer. The materials are chosen so as to control the separation force between the non-tacky polymer layer and the carrier layer. An optional adhesion controlling layer may be applied between the non-tacky polymer layer and the carrier layer.
Another known type of splicing tape includes a central paper layer or tissue layer which splits in use. For example, U.S. Pat. No. 5,901,919 shows an adhesive tape for flying reel change in paper finishing machines or the like, having a paper backing and a water-soluble self-adhesive composition, characterized in that the paper backing is coated on one side with a water-soluble self-adhesive composition while part of the reverse side of the paper backing is provided with a double-sided adhesive tape, which in turn has a readily splittable splicing paper backing which is provided on both sides with water-soluble self-adhesive composition.
When it is almost time to splice the new roll to the depleting roll, it is desirable to bring the new roll up to a rotational speed equal to the speed of the web from the depleting roll. Typically, this may be done by either driving the core on which the new roll is mounted, or by contacting a drive belt against the outer periphery of the new roll. When using a drive belt, it contacts against some portion of the width of the new roll, as illustrated at B in FIG. 1c. This typically occurs after the adhesive on the splicing tape has been exposed for bonding to the depleting web. It is undesirable for the drive belt to contact a significant portion of the exposed adhesive 21, as there is a chance that the splice tape could bond to the drive belt with sufficient strength to separate the splicing tape which could cause the new roll to rip or begin to unwind. One known method for minimizing this is to place bridge 29 over a portion of the exposed adhesive 21 of the splice tape for a width sufficient to protect the splice tape in the area B in which the drive belt could contact it. The bridge 29 may be a piece of adhesive tape, in which case it is applied adhesive face down, leaving the backing of the bridge tape exposed to contact the drive belt. The bridge may be a piece of paper or other material that may be conveniently adhered to the exposed adhesive 21, in which case the bridge 29 need not have any adhesive of its own. The bridge 29 may include holes that allow some of the adhesive 21 to remain exposed to strengthen the splice in the area of the bridge. It is also known to leave a small portion of the adhesive 21 exposed by placing the bridge a short distance back from the front of the adhesive 21. U.S. Pat. No. 4,905,924 discloses an alternative arrangement, in which portions of release liner extend along the length of the splicing tape, that is across the full width of the roll of material. The portions are separated from one another leaving lengths of splicing adhesive exposed.
A nose tab which is suitable for preparing a flying splice is described in GB 2,294,235. The ""235 reference discloses a nose tab for temporarily interconnecting the leading and trailing ends of the outermost turn of a could of sheet material. The nose tab has a first layer to be in use adhesively attached to the under surface of the leading end. The nose tab is characterized in that it has a second layer to be in use adhesively attached to the trailing end and/or to the leading end of the next to outermost turn. The first and second layers are bonded to one another across their mutually abutting faces in a manner permitting them to be peelingly separable in use. Double sided adhesive tape may adhere the trailing inner end of the old coil and leading outer end of the new coil.
Both permanent and flying splices should provide a flexible, strong connection between the two sheet materials or webs and should maintain substantially all of the properties of the sheet material; for example, if the sheet material is paper which can be printed or coated, the splice is preferably thin, flexible, printable, coatable and also repulpable. When using configurations like those of FIGS. 1a and 1b for preparing a flying splice, it is important that air cannot enter beneath the leading edge 35 of the outer turn 32 which would result in the roll unwinding itself at very high speeds thus interrupting the continuous production. To prevent air entering beneath the leading edge 35 of the outer turn 32, small destructible adhesive tabs 27 are sometimes applied not only at the noses of the leading edge 35 but, for example, also along the diagonal edges of the leading edge 35 in FIG. 1a or over the lateral edges of the leading portion of the outer turn 32 to the sides of the roll 30. Configurations like those of FIG. 1a and 1b are time consuming to apply and require the application of double-sided adhesive tapes and destructible nose tabs.
Other fields outside splicing tapes also provide internally delaminating articles. For example, U.S. Pat. No. 4,398,985 discloses a laminated construction having differential release characteristics which will yield a self-detackifying adhesive surface upon delamination. The laminate is produced by coating a film of a polymeric material onto one side of a face stock material and then laminating this construction to an adhesive which has been coated onto a release liner. The release liner is removed and the remaining portion of the laminate is affixed to a suitable substrate utilizing the exposed adhesive surface. The polymeric material is chosen so that upon delamination of the face stock from the substrate, it remains affixed to the adhesive coating. This results in a self-detackified adhesive surface on the substrate. The abstract of the ""985 reference states that such laminate constructions are useful for tags, labels, stickers, and the like as well as for sending credit, business, or membership cards on preprinted mailers to ultimate users. Because of the unique self-detackifying surface produced, both the face stock and substrate can be used and further handled or processed by hand or automated equipment.
Although the commercial success of available splicing tapes has been impressive, it is desirable to further improve the performance of splicing tapes.
One aspect of the present invention provides a splicing tape for splicing a leading edge portion of the outer turn of a roll of sheet material to a second sheet material. The splicing tape comprises a first tape component, a second tape component, and a third layer of adhesive separably joining the tape components. The first tape component includes a first backing, a first layer of adhesive on a first surface of the first backing, and a first barrier layer on a second surface of the first backing. The second tape component includes a second backing, a second layer of adhesive on a first surface of the second backing, and a second barrier layer on a second surface of the second backing. The third layer of adhesive separably joins the first barrier layer and the second barrier together.
In one preferred embodiment of the above splicing tape, the first and second backings comprise repulpable backings. More preferably, the first and second backings comprise cellulosic backings. Most preferably, the first and second backings comprise paper backings.
In another preferred embodiment of the above splicing tape, the first and second barrier layers prevent significant penetration of the third adhesive layer into the first and second backings. Preferably, at least one of the barrier layers comprises a lacquer.
In another preferred embodiment, at least one of the barrier layers comprises a filled barrier layer to control the bond strength between the filled barrier layer and the third adhesive layer. Preferably, the filled barrier layer comprises a silicone filled barrier layer. In another preferred embodiment, the barrier layer comprises a UV curable barrier layer.
In another preferred embodiment of the above splicing tape, the third layer of adhesive comprises a water-based adhesive. In another preferred embodiment, the third layer of adhesive comprises a synthetic resin emulsion based adhesive.
In another preferred embodiment of the above splicing tape, the third layer of adhesive comprises a gradient in the direction along the width of the tape.
In one embodiment, the above splicing tape, when in use, separates by cohesive separation of the third adhesive layer. In another embodiment, the splicing tape separates by delamination between the third adhesive layer and either of the first and second barrier layers.
In another embodiment, the splicing tape also includes a release liner on at least one of the first and second adhesive layers. Preferably, the release liner comprises a first portion and a second portion, each being independently separable from the splicing tape.
In another embodiment, the release liner comprises a first portion, a second portion, and a third portion. The first portion extends along the length of the splicing tape adjacent a first edge of the splicing tape, the third portion extends along the length of the splicing tape adjacent a second edge of the splicing tape, and the second portion extends along the length of the splicing tape between the first and third portions. The second portion of the release liner includes a plurality of weakened lines extending across the width of the second portion.
In any of the above embodiments, the splicing tape may include only a single barrier layer rather than first and second barrier layers. The splicing tape may include the barrier layer between the third adhesive layer and either of the first and second backings. In this embodiment, the splicing tape, when in use, preferably separates between the third adhesive layer and the barrier layer.
Another aspect of the present invention provides a method of making a splicing tape for splicing a leading edge portion of the outer turn of a roll of sheet material to a second sheet material. The method comprises the steps of: a) providing a first tape portion including a first backing and a first layer of adhesive; b) applying a first barrier layer on the first backing opposite the first layer of adhesive; c) providing a second tape portion including a second backing and a second layer of adhesive; d) applying a second barrier layer on the second backing opposite the first layer of adhesive; e) applying a third adhesive layer to either of the first and second barrier layers; and f) laminating the first and second tape portions together with the third layer of adhesive between the first and second barrier layers. In one preferred embodiment of this method, steps b) and d) each further comprise curing the barrier layer with UV light. In another preferred embodiment, steps b) and d) are performed concurrently.
Another aspect of the present invention provides a method of preparing a roll of web material for a flying splice. The method comprising the steps of: a) adhering a separable splicing tape to a roll of web material, wherein the splicing tape includes a release liner facing away from the roll and a layer of adhesive covered by the release liner; b) removing a first portion of the release liner along the length of the splicing tape to expose a first portion of the layer of adhesive, while maintaining a second portion of the adhesive tape along the length of the splicing tape covered with a second portion of the release liner; c) adhering the leading edge portion of the roll of web material to the first portion of the adhesive; and d) removing a first lengthwise segment of the second portion of the release liner while maintaining a second lengthwise segment, to thereby expose a first lengthwise segment of the second portion of the adhesive layer and to thereby maintain covered a second lengthwise segment of the second portion of the adhesive layer.
In one preferred embodiment of this method, it further includes the step of removing a third portion of the release liner along the length of the splicing tape, with the second portion between the first and third portions.
In another preferred embodiment of this method, step d) includes separating the second portion of the release liner along a weakened line.
In another preferred embodiment of this method, step d) includes removing a first and second segment of the second portion of the release liner from opposite sides of the second segment.
Certain terms are used in the description and the claims that, while for the most part are well known, may require some explanation. The term xe2x80x9cdelaminationxe2x80x9d as used herein refers to an adhesive separation mode of the splicing tape 10 whereby the splicing tape 10 separates between two adjacent layers so as to leave exposed the surfaces of the adjacent layers which had been in contact with each other previously. The term xe2x80x9csplittingxe2x80x9d as used herein refers to a cohesive separation mode of the splicing tape 10 whereby the splicing tape 10 breaks through one of its layers so as to leave exposed two inner surfaces of such layer.